/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *	  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jboss.el.lang;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import org.jboss.el.util.ReflectionUtil;



/**
 * @author Jacob Hookom [jacob@hookom.net]
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: markt $
 */
@SuppressWarnings({"rawtypes", "unchecked"})
public class FunctionMapperImpl extends ExtendedFunctionMapper implements
		Externalizable {

	private static final long serialVersionUID = 1L;
	
	protected Map functions = null;

	/*
	 * (non-Javadoc)
	 * 
	 * @see javax.el.FunctionMapper#resolveFunction(java.lang.String,
	 *	  java.lang.String)
	 */
	public Method resolveFunction(String prefix, String localName) {
		if (this.functions != null) {
			Function f = (Function) this.functions.get(prefix + ":" + localName);
			return f != null ? f.getMethod() : null;
		}
		return null;
	}
	
	public Method resolveFunction(String prefix, String localName, int paramCount) {
	   if (this.functions != null) {
		  Function f = (Function) this.functions.get(prefix + ":" + localName + ":" + paramCount);
		  return f != null ? f.getMethod() : null;
	  }
	  return null;
	}

	public void addFunction(String prefix, String localName, Method m) {
		if (this.functions == null) {
			this.functions = new HashMap();
		}
		Function f = new Function(prefix, localName, m);
		synchronized (this) {
			this.functions.put(prefix+":"+localName, f);
			this.functions.put(prefix+":"+localName+":"+m.getParameterTypes().length, f);
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
	 */
	public void writeExternal(ObjectOutput out) throws IOException {
		out.writeObject(this.functions);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.Externalizable#readExternal(java.io.ObjectInput)
	 */
	public void readExternal(ObjectInput in) throws IOException,
			ClassNotFoundException {
		this.functions = (Map) in.readObject();
	}
	
	public static class Function implements Externalizable {
	
		protected transient Method m;
		protected String owner;
		protected String name;
		protected String[] types;
		protected String prefix;
		protected String localName;
	
		/**
		 * 
		 */
		public Function(String prefix, String localName, Method m) {
			if (localName == null) {
				throw new NullPointerException("LocalName cannot be null");
			}
			if (m == null) {
				throw new NullPointerException("Method cannot be null");
			}
			this.prefix = prefix;
			this.localName = localName;
			this.m = m;
		}
		
		public Function() {
			// for serialization
		}
	
		/*
		 * (non-Javadoc)
		 * 
		 * @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
		 */
		public void writeExternal(ObjectOutput out) throws IOException {
			out.writeUTF((this.prefix != null) ? this.prefix : "");
			out.writeUTF(this.localName);
			out.writeUTF(this.getMethod().getDeclaringClass().getName());
			out.writeUTF(this.getMethod().getName());
			out.writeObject(ReflectionUtil.toTypeNameArray(this.getMethod().getParameterTypes()));		
		}
	
		/*
		 * (non-Javadoc)
		 * 
		 * @see java.io.Externalizable#readExternal(java.io.ObjectInput)
		 */
		public void readExternal(ObjectInput in) throws IOException,
				ClassNotFoundException {
			
			this.prefix = in.readUTF();
			if ("".equals(this.prefix)) this.prefix = null;
			this.localName = in.readUTF();
			this.owner = in.readUTF();
			this.name = in.readUTF();
			this.types = (String[]) in.readObject();
		}
	
		public Method getMethod() {
			if (this.m == null) {
				try {
					Class t = Class.forName(this.owner);
					Class[] p = ReflectionUtil.toTypeArray(this.types);
					this.m = t.getMethod(this.name, p);
				} catch (Exception e) {
					throw new RuntimeException("Error loading function", e);
				}
			}
			return this.m;
		}
		
		public boolean matches(String prefix, String localName) {
			if (this.prefix != null) {
				if (prefix == null) return false;
				if (!this.prefix.equals(prefix)) return false;
			}
			return this.localName.equals(localName);
		}
	
		/* (non-Javadoc)
		 * @see java.lang.Object#equals(java.lang.Object)
		 */
		public boolean equals(Object obj) {
			if (obj instanceof Function) {
				return this.hashCode() == obj.hashCode();
			}
			return false;
		}
		
		/* (non-Javadoc)
		 * @see java.lang.Object#hashCode()
		 */
		public int hashCode() {
			return (this.prefix + this.localName).hashCode();
		}
	}

}
